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Quick Start Tutorial PDF Print E-mail
Written by Administrator   
Friday, 21 December 2007
This tutorial showing an example of simple job submission on the Grid.

Create a Proxy

After registering and becoming a member of a Virtual Organization (VO), log into a User Interface server to use Grid client tools.  The first thing that must be done before using the Grid is to create a voms proxy.  The proxy is a short lived (default 12 hours) certificate, that is used instead to protect your long term user certificate.  The proxy certificate also provides single sign-on capabilities for the life time of the proxy certificate.

VOMS Proxies

The Virtual Organisation Membership Service(VOMS) allows a proxy to have extensions containing information  about your the VO membership.  It is possible for you to be member of more than one VO at the same time.  When you like to access the resources available to a particular VO, you can create a proxy specifying that VO.

  • To create a proxy with access to TWGrid VO, use:
 
    $ voms-proxy-init -voms twgrid

If the command is successful, the proxy will be written in /tmp/x509up_<uid>, where <uid> is the Unix UID of the user.

  • If the proxy cannot be created, please check the following:

 

did you provide the correct pass phrase?

is your user certificate and key installed in ~/.globus directory?

does the certificate and key have the proper permissions?

Is the DN created by the certificate different with the DN registered in the VO database?

  • print information about a proxy 

$ voms-proxy-info -all

  • destroy an existing proxy before expiration

 $ voms-proxy-destroy

More VOMS introduction can be found at:

 

 




Job Examples

In this section simple example will be introduced to show the whole process. More examples could be found at http://www.bo.infn.it/alice/introgrd/edg2/node10.html and http://www.euasiagrid.org/wiki/index.php/GLite_Job_Management

Simple Job Submission: JDL file only

To submit a job, the user must first create a Job Description Language (JDL) file.  The JDL file describes important characteristics of your job such as the executable of your job and output files to be returned after your job is complete.

An example of a minimal JDL file is show below:

1. create a JDL file "hostname.jdl" with the following content

Executable = "/bin/hostname";
StdOutput = "hostname.out";
StdError = "hostname.err";
OutputSandbox = {"hostname.err","hostname.out"};

2. After creating the JDL you can verify that there are resources available for your job:

$glite-wms-job-list-match -d hostname.jdl

Connecting to the service https://wms.euag.org:7443/glite_wms_wmproxy_server

==========================================================================

COMPUTING ELEMENT IDs LIST
The following CE(s) matching your job requirements have been found:

*CEId*
- ce.euag.org:2119/jobmanager-lcgpbs-gilda

=========================================================================

3. To submit the job, use the following command:

$ glite-wms-job-submit -d $USER -o jobid hostname.jdl

Connecting to the service https://wms.euag.org:7443/glite_wms_wmproxy_server


====================== glite-wms-job-submit Success ======================

The job has been successfully submitted to the WMProxy
Your job identifier is:

https://wms.euag.org:9000/tcl6gKsrMJm8TReyXcc7tQ

The job identifier has been saved in the following file:
/home/UPM04/jobid

==========================================================================

4. Check the job status with the following command:

$ glite-wms-job-status -i jobid

which prints jobs status(e.g. Waiting, Scheduled, Done) and the Computing Element (CE) where the job is run at.

*************************************************************
BOOKKEEPING INFORMATION:

Status info for the Job : https://wms.euag.org:9000/tcl6gKsrMJm8TReyXcc7tQ
Current Status: Running
Status Reason: Job successfully submitted to Globus
Destination: ce.euag.org:2119/jobmanager-lcgpbs-gilda
Submitted: Fri Jul 31 05:20:54 2009 UTC
*************************************************************

The seven status flag values and their meaning are listed in the tab below:

  •  SUBMITTED: Job has submitted to RB/WMS.  
  •  WAIT: job match making for finding available resources 
  •  READY: job being sent to executing CE
  •  SCHEDULED:  job shceduled in the CE Queue system 
  •  RUNNING: job is executing on a WN 
  •  DONE: job is completed without any errors 
  •  CLEARED: job output is retrieved 
  •  ABORT:  job aborted
 

 

 

 

 

 

 

 

 

5. When the job is completed(status = Done), retrieve the job output with this command:

$ glite-wms-job-output -i jobid
Connecting to the service https://wms.euag.org:7443/glite_wms_wmproxy_server 

================================================================================

JOB GET OUTPUT OUTCOME

Output sandbox files for the job:
https://wms.euag.org:9000/tcl6gKsrMJm8TReyXcc7tQ
have been successfully retrieved and stored in the directory:
/tmp/jobOutput/UPM04_tcl6gKsrMJm8TReyXcc7tQ

================================================================================

In order to inspect the job output, list the files in the indicated directory and show the content of the output file(s).

[UPM04@ui ~]$ cd /tmp/jobOutput/UPM04_tcl6gKsrMJm8TReyXcc7tQ
[UPM04@ui UPM04_tcl6gKsrMJm8TReyXcc7tQ]$ ls -la
total 12
drwxr-xr-x 2 UPM04 UPM04 4096 Jul 31 05:51 .
drwxrwxrwt 8 root root 4096 Jul 31 05:51 ..
-rw-rw-r-- 1 UPM04 UPM04 0 Jul 31 05:51 hostname.err
-rw-rw-r-- 1 UPM04 UPM04 13 Jul 31 05:51 hostname.out
[UPM04@ui UPM04_tcl6gKsrMJm8TReyXcc7tQ]$ cat hostname.out
wnc.euag.org
[UPM04@ui UPM04_tcl6gKsrMJm8TReyXcc7tQ]$
 
Last Updated ( Monday, 21 September 2009 )
 
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